Clean Air, Healthy Home

When people talk about pollution, they immediately think of smog, traffic and industry. However, there is another type of pollution that can have a considerable impact on human health: indoor pollution. This article explains what indoor pollution is, what causes it and, most importantly, how to reduce it in order to increase the comfort of your home.

Indoor pollution: what it is and features

Indoor (i.e., ‘internal’) pollution is a concept that refers to the presence of pollutants in the air inside enclosed spaces such as houses, schools and offices.
In the age in which we live, many people tend to live most of their time in enclosed spaces such as these for work, study, eating, sleeping, and recreation; it goes without saying that the air one breathes in these places can have a serious effect on one’s health, especially in the long term. It is therefore crucial to understand what indoor pollution is and how to prevent or reduce it as much as possible.
The most common agents responsible for indoor pollution are volatile organic compounds (VOCs), carbon dioxide (CO2), fine dust (PM10, PM2.5), allergens (pollen, pet dander, dust, mould(1)…), carbon monoxide (CO) and radon. These pollutants can originate from various sources in or near enclosed spaces.

What are the effects of indoor pollution on human health

Indoor pollution can have significant effects on human health, especially as a result of very prolonged exposure.
The effects vary depending on the type and concentration of the pollutants, but also on the vulnerability of the subjects; for example, the most vulnerable are children, the elderly, pregnant women and people suffering from chronic diseases (asthma, allergies, heart disease).
Short-term effects can be noted:

• eye, nose and throat irritation;
• respiratory problems (coughing, breathing difficulties and worsening of pre-existing conditions such as asthma and bronchitis);
• headaches and dizziness;
• nausea and fatigue.

There is a specific term, Sick Building Syndrome, which describes a series of symptoms that occur in particularly polluted indoor environments.
These symptoms can be:

• irritation of the skin or mucous membranes;
• difficulty concentrating;
• a feeling of persistent tiredness and general malaise.

In the long term and especially in susceptible individuals, indoor pollution can lead to serious health problems, such as chronic respiratory diseases, cardiovascular diseases, cancers and neurological damage.

What are the main sources of indoor pollution

The pollutants found in the air inside enclosed spaces are almost always invisible and can come from different sources.
First of all, it has to be said that enclosed spaces are never watertight in relation to external environments, on the contrary: there is a continuous dialogue between inside and outside (just think of the times when windows are kept open). For this reason, often many of the agents that cause environmental pollution also cause indoor pollution. In fact, polluting particles outside can ‘travel’ through the air (or be carried on shoes and clothes) and ‘settle’ in houses, schools and offices.
In this regard, city dwellers are likely to be affected by draining gases, particulate matter and nitrogen oxides emitted by vehicular traffic, as well as sulphur dioxide, heavy metals and fine particles that are emitted through production processes by industries. Those who live far from the city are unfortunately no less immune: the use of fertilisers and pesticides in agriculture releases ammonia and methane into the air, while forest fires release large quantities of particulate matter and carbon monoxide. In general, then, it should not be forgotten that even simple natural dust, resulting from deserts, volcanoes or normal soil erosion, are pollutants.
However, there are sources of pollution that are specific to enclosed internal spaces. They are many and often completely unsuspected because they derive from objects, materials and activities that are part of everyday life inside homes. Here are the most common ones.

Building and furnishing materials

From the earliest stages of building or renovating a house, one has to think about possible sources of indoor pollution.
For example, PVC or laminate windows and doors or flooring may release phthalates and other potentially harmful substances. Furniture made of chipboard or plywood is often treated with resins that release formaldehyde. Finally, some paints or glues have a bad impact on the environment and human health, as they emit volatile organic compounds (VOCs), formaldehyde and other chemicals into the air.

Household chemicals

People use chemicals daily in their homes, schools and offices to clean and disinfect surfaces. However, one must be aware that many commercially available cleaning agents and disinfectants contain VOCs that evaporate into the air during use. Volatile organic compounds are also often released by air fresheners and even by seemingly innocent scented candles (or incense), which may release fine particles during the burning process. Finally, insecticides also release toxic substances into the air.

Cooking and heating systems

During combustion, gas cookers release small amounts of carbon monoxide and nitrogen monoxide. These elements, along with fine particulate matter, are also released by the action of gas or wood-burning stoves. Finally, care must be taken with fireplaces: when they are not well ventilated, they may pollute the indoor air with toxic particles and gases.

Excessive humidity

It is essential to effectively manage humidity in one’s own homes, so as to create the ideal micro-climate for the well-being and living comfort of those living there. If the humidity level exceeds optimal levels for a long period, condensation may occur, which encourages the proliferation of bacteria and moulds. Moulds are considered real agents of indoor pollution, as they release spores that can cause allergies and respiratory problems.

Dusts and allergens

These elements are also considered pollutants. These include dust mites, which are frequently found in fabrics such as carpets, curtains and mattresses. Pollens come from outside, but easily enter the home through open windows, often accumulating invisibly. Finally, pet hair can carry allergens and pollutant particles.

Tobacco Smoke

There is no need to explain how harmful smoking can be to a smoker’s health. However, it is also important to consider it as an agent of indoor pollution, not only for smokers but also for people who are affected by passive smoking. Cigarettes and cigars produce over 4,000 chemicals, many of which are toxic if breathed in.

Electronics and technological devices

As much as technology makes everyday life more practical and pleasant, one must be aware that it can be a polluting agent. For example, printers and photocopiers release ozone, fine particles and VOCs during operation. Other electronic devices such as televisions and monitors, especially older models, may also release small amounts of VOCs and other substances through their plastic materials and circuits. In addition, electronic devices such as computers, modems and routers emit heat, which can contribute to drying out the air and favouring the suspension of fine dust and allergens. Dust can also accumulate in electronic devices, which is attracted by electrostatic load; this dust can contain allergens and harmful particles that are released into the air every time the devices are touched or switched on. Finally, care must be taken with old or malfunctioning components such as spent batteries and damaged devices that can release unwanted toxic substances if not disposed of properly.

Daily activities

Based on the above assumptions, it will be easy to understand how many of the human daily activities can generate small but substantial sources of indoor pollution.
For example:

• clean: the use of cleaning agents, disinfectants, surface sprays or glass sprays generates VOCs and other volatile chemicals, all the more so if sulphate and ammonia-based products are used;
• washing and drying laundry: some cleaning agents release VOCs and synthetic fragrances, while dryers without external ventilation can increase humidity in the home, contributing to the formation of mould;
• taking a shower or bath: the humidity level is raised and personal care products such as perfumes, spray deodorants or lacquers, which contain VOCs, are used;
• use domestic appliances such as cookers or fireplaces, gas cookers or vacuum cleaners without HEPA filters;
• smoking, lighting candles or burning incense;
• do manual work using glues, adhesives, paints or solvents that can release VOCs even days later;
• cooking: frying, grating and baking generate fine particles, while overheated oils and fats release VOCs into the air.

Radon gas

Little known, radon gas is a radioactive gas of natural origin and originating in the soil; it is produced by the decay of uranium present in soil, rocks and even some building materials.
An odourless, colourless and tasteless gas, it is considered one of the main causes of indoor pollution and, unfortunately, can have harmful effects on health (it is among the main factors in lung cancer). This gas settles in enclosed spaces through cracks in foundations or floors, cracks in walls, connection points between pipes or electrical cables, wells or aquifers from which domestic water comes.
In the long run, it is easy for it to accumulate in closed rooms, especially cellars and lower floors of houses.

How to reduce indoor pollution: 10 basic tips

It will be clear by now how crucial it is to reduce sources of indoor pollution in order to improve air quality. The goal is to be able to live, work and study in healthy environments that promote personal well-being, also in the long term.
A number of tips are given here, some of which can be put into practice immediately, to reduce indoor pollution.

Reducing sources of pollution

To decrease indoor pollution, the first thing to do is of course to strive to reduce its sources, so as to lower its levels in the long run. Here are some of the daily actions you can take to reduce sources of indoor pollution:

• limit or avoid the use of chemicals, such as cleaning products and air fresheners;
• choose products such as paints, adhesives and cleaning agents that are specifically free of (or low in) volatile organic compounds;
• eliminate the use of fossil fuels: for example, wood or coal stoves can be replaced by pellet stoves or electric heating;
• avoid smoking in the home: tobacco is one of the main causes of indoor pollution, so its use should be avoided in enclosed spaces;
• get rid of any obsolete technological devices by enamelling them correctly;
• use extractor hoods in kitchens and fans in bathrooms to reduce fumes, vapours and moisture.

Ensure frequent and effective ventilation

Indoor pollution agents are harmful when they settle or hover in the air of enclosed spaces for a long time, forcing inhabitants to be exposed to them for a long time. No matter how hard we try to reduce the sources of pollution, it will be almost impossible to eliminate them completely, so a key action is to ensure good ventilation of indoor spaces, so as to avoid precisely the persistence of pollutants in the air.
Rooms should therefore be aired daily, at least 15 minutes a day, preferably in the morning and in all seasons. A change of air should also be done after every use of potentially polluting sources (detergents and cleaning products, scented candles, glues and paints, cooking food…).
To effectively ventilate the house and also contribute to environmental sustainability, a controlled mechanical ventilation (VMC) system can be installed, which guarantees a constant and energy-efficient change of air. Another very effective system is the classic window opening system; to avoid excessive dispersion of thermal energy, it is advisable to install window and door frames that allow for a discrete but continuous change of air, such as those with special projecting openings (bottom-hung, tilt, pivot window… this article lists all types of openings). Some windows and doors also include a micro-ventilation system, which helps to avoid stagnation of stale air.

Installing high-efficiency windows and doors

If you are going to replace windows and doors, you should know that they can play a key role in reducing indoor pollution, naturally if you choose efficient windows and doors with the right features.
In this regard, it is recommended to install thermal break aluminium windows and doors. The latter guarantees excellent thermal insulation, which helps to maintain the desired internal temperature. By avoiding heat loss, the use of heating systems (but also cooling in summer) is reduced, thus reducing the emission of pollutants produced by such systems. Thermic insulation also helps to maintain a steady and controlled level of humidity, which drastically reduces the formation of condensation and the proliferation of mould.
Aluminium is also a very resistant material, thus preventing the entry of smog, fine dust, allergens, toxic gases and other pollutants from outside. Moreover, it does not require any special products to be cleaned effectively, thus helping to limit the use of cleaning chemicals.

Choosing materials and furniture consciously

The choice of building and furnishing materials can have a considerable impact on reducing indoor pollution.
The first thing to do is to find out the composition of the different materials: it is essential that they are as environmentally friendly as possible, made of natural materials and free of formaldehyde. One must also make sure that any resins, glues and paints do not release VOCs or other airborne chemicals, but are certified, certified as safe for humans and the environment.
It is also important to reduce the possibility of dust and allergen accumulation, especially in environments frequented by people with asthma, allergies or respiratory problems. In these cases, it is good to choose materials that tend to attract less dust: materials that are smooth, non-electrostatic and easy to clean. Some examples are metals such as steel, aluminium and copper, but also glass, non-electrostatic plastic, porcelain or stoneware, polished or laminated wood, and eco-leather. Materials to avoid, i.e., those that attract the most dust and/or are the most difficult to clean, are natural fabrics (wool, cotton, velvet…), rough surfaces such as raw wood or natural stone, untreated plastic, carpets and rugs.

Making the home practical for cleaning and maintenance

A clean house is definitely a house that is less affected by indoor pollution, especially dust, dust mites and allergens. To make the task of cleaning quick and easy, and above all to avoid using too many chemicals that can increase pollution, it is important to make the house practical to clean. One can therefore choose the materials seen above, which attract less dust and are quicker to dust frequently. Aluminium, for example, is a perfect material for windows and doors and other furnishings, as it only requires a simple cloth soaked in water for cleaning (which should not be too frequent, however).
For a practical home, it is also useful to reduce objects and hindrances to cleaning, for example by adopting a minimal furnishing style that discourages the accumulation of dust. Carpets, curtains and other fabrics can be placed in such a way that they are easy and quick to remove for washing. Finally, it is useful to purchase a hoover equipped with a HEPA filter, which is able to eliminate allergens and fine dust.

Prefer natural solutions

We have seen how some cleaning, hygiene and home wellness products carry chemicals that leach into the air, contributing substantially to indoor pollution. Given that certain products must be used anyway, it is worth converting to the use of natural products, spending some time searching for cleaning agents that are ecological and therefore friendly not only to the environment, but also to human health. All-natural methods can sometimes also be used, cleaning with products such as vinegar and bicarbonate of soda.
When you want to perfume your home, it is equally important to choose candles, air fresheners and fragrances that are as natural as possible. For example, you can replace synthetic candles with those made of beeswax or soy, and use foods such as citrus fruits, spices or herbs to perfume rooms.

Controlling systems and appliances regularly

Whenever possible, the ideal way to reduce indoor pollution would be to replace all obsolete household appliances in favour of the latest generation models that are more efficient energy use and release less pollution into the air. Their daily use also counts: they should be used sparingly, disconnecting sockets when not in use. As for gas cookers, which release small but continuous doses of carbon monoxide, one can consider replacing them with induction cookers.
It is also important to carry out regular maintenance of systems and devices to reduce their potential for indoor pollution. To ensure that boilers always remain efficient and do not release harmful emissions, it is good to have them serviced regularly. Then, either by yourself or with the help of experts, it is important to frequently clean the filters of heating and conditioning systems, as well as hoods and dehumidifiers.

Monitoring the humidity level

Humidity is one of the main friends of indoor pollution, as it generates the formation of condensation, fungus and mould. In order to prevent this, it is important to regularly monitor the humidity level indoors, ensuring that it always remains between 30 and 50 per cent.
To adjust the humidity level, humidifiers or dehumidifiers can be used, the latter especially in rooms where humidity tends to build up more regularly (bathroom, kitchen, laundry room). It is also important to close any cracks in the walls and to repair water leaks and infiltrations, which could encourage excessive humidity.

Keeping air quality controlled

Air quality monitoring makes it possible to identify the presence of pollutants, keep critical parameters under control and take preventive or corrective measures to improve the comfort and health of inhabitants.
There are several methods to do this, for example:

• indoor pollution sensors: these are electronic devices designed specifically to monitor air quality by dimensioning the number of pollutants in the air (suspended particles, VOCs, carbon dioxide, carbon monoxide, relative humidity…);
• radon gas tests: there are kits that allow the presence of radon gas to be detected at a variable location and over a variable period of time. They are particularly useful in areas with high natural radioactivity;
• carbon monoxide detectors: essential in any case where gas cookers, fireplaces, gas stoves or combustion heating systems are present;
• smart monitoring devices: some monitoring devices can connect to smartphones via apps to receive real-time security notifications and provide customised suggestions based on the data collected;
• professional monitoring systems, such as environmental consulting services and industry-specific tools, which are mainly useful in sensitive environments such as schools, offices or houses where vulnerable people live.

Making use of air purifiers

Despite all efforts, it will be difficult to completely eliminate pollutants in the air, so it may be useful to purify it using special devices. Air purifiers exist precisely for this purpose and help filter out mainly dust and allergens. They can also have different functions depending on their features; for example, purifiers with HEPA filters remove fine particles, pollen and allergens, while purifiers with activated charcoal are useful for removing odours and VOCs. One can also make use of ionisers, which help remove polluting particles by charging them electrically; in this case, however, it is essential to choose models that do not produce ozone.
Finally, do not forget that plants can also have excellent air-purifying properties. Better not to exaggerate if you live in environments that are already very humid, but in general, plants absorb allergens, carbon dioxide and VOCs and release oxygen, making any place healthier. It is advisable to opt for plants with a higher purifying ‘power’, such as sansevieria, pothos, spatiphyllum and areca palm.

Why choose aluminium windows and doors to reduce indoor pollution

As we have seen, windows can contribute significantly to reducing indoor pollution in one’s own homes. When replacing windows, it is advisable to opt for aluminium windows with thermal break and features better suited to living comfort, such as those proposed by METRA Building.
METRA Building aluminium windows:

• are available in multiple types of openings, promoting micro-ventilation and the proper exchange of air within rooms;
• equipped with the latest generation of thermal break, they guarantee highly effective thermic insulation, which makes it possible to reduce the use of heating and cooling systems. This has positive effects not only on reducing the pollution caused by such systems, but also on energy savings and eco-sustainability;
• are installed installation with impeccable by experienced professionals. The danger of draughts and seepage that could contribute to an excessive level of humidity will thus be permanently and durably eliminated;
• are made of an extremely resistant and protective material, assisted by state-of-the-art sealing elements. This allows the window to leave out any kind of external pollutants: smog and fine dust, pollen and other allergens, toxic gases (such as carbon monoxide) typical of urban and busy areas;
• are made from a 100% recyclable, non-toxic material that does not emit VOCs or other harmful substances, unlike cheaper or chemically treated materials;
• are made of a material that does not accumulate dust or soil and is easy to clean with a simple wet cloth, thus avoiding chemical and abrasive cleaning agents that could release harmful substances;
• can be customised in a wide range of colours and finishes. The colours are produced by oxidation or painting, without the use of chemical compounds and guaranteeing a long-lasting effect.